Examples of known molding systems are (amongst others): (i) the HyPET™ Molding System, (ii) the Quadloc™ Molding System, (iii) the Hylectric™ Molding System, and (iv) the HyMet™ Molding System, all manufactured by Husky Injection Molding Systems Limited (Location: Bolton, Ontario, Canada; www.husky.ca).
U.S. Pat. No. 4,272,466 (Inventor: Harris; Published: Jun. 9, 1981) discloses a system and method of temperature control for a plastics extruder uses a deep well sensor and a shallow well sensor in each temperature control zone along an extruder barrel. The temperature indications of these sensors are not combined. The shallow sensor detects temperature near the barrel surface. An associated controller compares the sensor temperature with a manually preset temperature set point. The differences between the detected and set temperature are used by the controller to effect heating or cooling of its associated temperature control zone. Each deep sensor is located proximate the bore in which the plastic is moved. The deep sensor temperature indication is compared with the set point of a second controller. Variations of the deep temperature from the set point generate an error signal that is applied to the first, shallow well temperature controller to vary its set point. A melt temperature control addition can be made by adding a melt temperature sensor directly in the path of melt between the extruder screw and the extrusion die. A further controller compares its set point with that of the melt temperature and modifies the deep temperature controller set points of the several zones along the extruder barrel to correct the melt temperature.
U.S. Pat. No. 4,309,114 (Inventor: Klein et al; Published: 1982 Jan. 5) discloses an apparatus and a method in which temperature of a barrel inner surface and temperature of a screw conveyor outer surface of a plasticating extruder are varied, alternately, in repeated steps, independent of one another along at least a portion of the solids conveying zone of the extruder, while a production effectiveness parameter simultaneously is monitored, until the monitored production effectiveness parameter is optimized and the production effectiveness of the extruder is at a desired maximum.
U.S. Pat. No. 5,149,193 (Inventor: Faillace; Published: Sep. 22, 1992) discloses an extruder temperature controller for an extruder barrel and a method for controlling the temperature of an extruder barrel. The controller includes a device for determining an actual screw speed and for storing a plurality of screw speeds. Each member of the plurality of stored screw speeds has a corresponding stored temperature reset value. The extruder temperature controller has a device for comparing and selecting that compares the actual screw speed to each of the plurality of stored screw speeds and selects a default screw speed. The default screw speed has a smaller deviation from the actual screw speed than any other member of the compared, stored screw speeds. The controller further includes a device for generating a control output driver signal to a heat exchanger. The control output driver signal is the corresponding stored temperature reset value for the default screw speed. The adaptive reset value for a specific speed is derived for each extruder barrel zone for each profile table section of setpoints and parameters for a particular extrusion material and particular process.
U.S. Pat. No. 5,272,644 (Inventor: Katsumata et al; Published: Dec. 21, 1993) discloses an apparatus for controlling a heating temperature, especially for heating a resin in an injection mold machine, an extruder and the like. The apparatus includes (i) a control device for controlling a heating means and the state of a heated barrel and (ii) a condition compensating device for issuing a compensation input to the heaters respectively in response to a reset of the control device, depending on the kinds of resin materials and molding conditions so as to prevent insufficient moldability in the injection mold machine and a deterioration of resin.
U.S. Pat. No. 5,597,588 (Inventor: Totani et al; Published: Jan. 28, 1997) discloses a barrel temperature control apparatus for an injection molding machine that can execute the barrel temperature control in such a way as to optimize the disturbance suppression characteristics. The temperature control section includes the manipulated variable addition and subtraction section at the rear stage of the PID control section in such a way that the barrel temperature of the injection molding machine can be controlled under both feedback and feed-forward. Further, when the same products are molded continuously, the barrel temperature is feed-forward controlled on the basis of the learned change manipulated variable.
U.S. Pat. No. 6,104,006 (Inventor: Shigeru et al; Published: Aug. 15, 2000) discloses a method and an apparatus for the programmed temperature control of a heating barrel provides for programmed temperature control in which a thermal sensor can be set selectively in either or any of plural sensor holes on the feeding zone of the heating barrel. By sensing the temperature at the most appropriate position with in the feeding zone, the molding injection is adapted to various resins with different properties, preventing clogging of resin in the heating barrel and changed color of molded articles.
U.S. Pat. No. 6,755,564 (Inventor: Eiva; Published: Jun. 29, 2004) discloses an extruder temperature controller for an extruder barrel. The extruder temperature controller includes means for determining an actual screw speed and has means for storing a plurality of screw speeds. Each member of the plurality of stored screw speeds has a corresponding stored temperature reset value. The extruder temperature controller has a means for comparing and selecting that compares the actual screw speed to each of the plurality of stored screw speeds and selects a default screw speed. The default screw speed has a smaller deviation from the actual screw speed than any other member of the compared, stored screw speeds. The controller further includes a means for generating a control output driver signal to the heat exchange means. The control output driver signal is the corresponding stored temperature reset value for the default screw speed. The invention further includes a means for delaying a control alarm for a predetermined time when the means for generating a control output driver signal to the heat exchange means operates at or near maximum capacity. The invention includes a method for controlling the temperature of an extruder barrel.
U.S. Pat. No. 6,852,257 (Inventor: Eiva; Published: Feb. 8, 2005) discloses a method for operating an extruder temperature controller. The method can include sensing an actual screw speed for an extruder screw in an extruder barrel. The extruder barrel has at least one heat exchange means. The method can then involve indexing and storing a plurality of screw speeds. Each of the stored screw speeds corresponds to a temperature reset value. Comparing the actual screw speed with each of the stored screw speeds can then be performed. Selecting one of the stored screw speeds can then occur. The selected screw speed is a member of the plurality of stored screw speeds having a value most arithmetically equivalent to the actual screw speed. The step of selecting retrieves the temperature reset value corresponding to the selected, stored screw speed. Generating a control output driver signal to the heat exchange means can occur. The control output driver signal is responsive to the retrieved temperature reset value. The invention includes delaying a control alarm for a predetermined time when generating a control output driver signal to the heat exchange means is at or near maximum capacity.